Military vehicles are under constant threat of attack—especially aircraft. There are a variety of possible threat sources, for example enemy aircraft and ground-based weapons, such as shoulder launched missiles (SLMs). If successful, enemy attacks are devastating and almost certainly result in loss of the life of the aircraft's occupants. Accordingly, it is of utmost importance to immediately identify threats and deploy available countermeasures so as to prevent enemy attacks from being successful.
An aircraft's engine emits large amounts of heat, resulting in thermal infrared (IR) radiation. SLMs may use an IR seeker head missile to target the aircraft, allowing accurate targeting with little need for aiming accurately. An IR seeker head may lock on the heat signature of the aircraft and may distinguish the aircraft's heat signature from other heat signatures. Depending on the distance of the SLM source from the aircraft, the time from the SLM being fired until impact may be as short as 2-5 seconds. If the aircraft is to deploy countermeasures to prevent impact, it must do so immediately upon detecting the SLM.
SLMs risks are not limited to military aircraft. In the past, terrorist groups have targeted commercial aircraft. Accordingly, commercial aircraft may also avert disastrous SLM attacks by using countermeasure technology.